Disambiguating between different indoor regions of a structure can be difficult using transceivers, especially short-range wireless transceivers (e.g., WiFi access points, femtocells, Zigbee transceivers, Bluetooth® transceivers, etc.), alone. For example, indoor regions may be different floors of a building or portions of floors in a building or different portions of a floor. In this case, signals from wireless transceivers (WTs) in different regions can be received by a single mobile station (MS). Even though the MS is in a first region, the signal strength received from a WT in a second, different, region may be stronger than the signal strength of a signal received from a WT in the first region. This is especially true near portals such as staircases and elevator shafts, e.g., due to waveguide effects of these structures.